The present invention relates generally to the field of electrical immobilization weapons of the type which impart an electrical impulse to immobilize a human target by inducing involuntary muscular contractions, and more particularly, to an improved ammunition cartridge for the electrical discharge weapon which provides for a longer arc path at the target by lengthening potential arc paths across the exterior surfaces of the ammunition cartridge, while still maintaining a conveniently small size for use and storage. Electrical discharge weapons, commonly sold under the trademark TASER, are weapons that connect a human target to a remote electrical power supply by means of a pair of darts and trailing conductors, so that the human target can be disabled by an electrical shock from the weapon. The typical power supply of an electrical discharge weapon produces low amperage shocks of 50 KV. Human beings can be disabled by shocks of much lower voltage, however, the higher voltage is needed to ionize air paths, so electrical currents can penetrate otherwise insulated garments worn by the human target to complete the shocking circuit through the body. 50 KV from a typical electrical discharge weapon will arc across an air gap of approximately two inches.
Typical ammunition cartridges for electrical discharge weapons launch their darts by the force of explosion of a chemical propellant (primer fired), or by force resulting from the release of compressed gas or spring tension. Previous primer fired ammunition cartridges are substantially rectangular in shape, and formed of a high impact plastic housing and include wire chambers positioned adjacent interior walls of the housing. The chambers open at an exit surface and are positioned at an angle with respect to each other within the cartridge housing.
When the power supply for the weapon is energized, electrical current travels from a power supply electrode to the primer and sparks through the propellant where it arcs therefrom to the conductor in the wire chamber. The current then travels through the conductor to the attached dart assembly and arcs therefrom across the exit surface to the second dart assembly. The current continues to travel through its attached conductor to an opposed electrode of the power supply, or vice versa, depending on the polarity of the supply transformer poles. The propellant contained in the primer detonates and launches the darts from the cartridge. The darts separate from each other in angled flight, and open the detonation circuit as its current can no longer complete an arc path between the darts. If the darts come within arcing distance of a human target, the shocking circuit will complete through and disable the target.
A problem with primer fired ammunition cartridges is that the shocking current will arc through the shortest available air gap. Based upon the design of currently available primer fired ammunition cartridges, the shortest distance is between the primer exposed on the rear surface of the housing, and an adjacent side surface of the housing. Therefore, the maximum total distance that current might arc from the darts seated in garment clothing on the human target must be less than the distance between the primer located on the back surface of the cartridge, and a termination positioned on the side surface of the cartridge. If the distance between the target's clothing is greater than this distance, the shocking current will not arc through the target, and therefore, the darts will not subdue the target.
Additionally, the circuit might arc even a shorter distance at the target because of the phenomenon known as arc tracking, particularly if prior usage of the weapon has fouled the ammunition chamber with conductive carbon residues. Accordingly, if a human target is wearing clothing that is further distant from the body, then the arc path of the ammunition cartridge, the target will not be shocked or disabled even if both darts contact their clothing while the weapon is energized. For example, a human target might not be disabled if one dart impaled into his or her shirt over the chest while the other dart impaled into his or her shirt lapel or loose hanging pants fabric, or if both darts landed in a thick jacket or coat. Consequently, a need exists to extend or lengthen the arc path on the ammunition cartridge so that the arc is available at the target to penetrate clothing based upon a 50 KV power source.
A second problem associated with previous primer fired ammunition cartridges is that over a period of time the receiving port of the weapon can become damaged due to the explosive forces of firing the ammunition. Typical primer fired cartridges include a cantilever which seats into a conforming depression in the plane of one of the port walls of the weapon to lock the cartridge into the receiver of the weapon during firing. When the charge in the ammunition cartridge is detonated, resultant forces cause the cantilever to move forward and collide with the corresponding wall of the depression, and therefore the cartridge is restrained within the receiver. With time and exposure to the elements, the structural integrity of the weapon can become compromised, and as the sides of the cartridges cantilever repeatedly strikes against the corresponding wall of the seating depression in the wall of the receiver port, the receiver's plastic can fracture and chip off. If enough plastic dislodges from the wall, resultant forces might fire the entire cartridge out of the weapon after the cartridge's charge is detonated. This disconnects the darts from the weapons power supply, and the remote target will not be shocked thereafter. Consequently, a need exists for an improved design which will prevent the ammunition cartridge from being ejected from the weapon after repeated use.